On 10.10.19 18:18, Julien Grall wrote:
Hi,
Hi Julien
On 10/8/19 4:25 PM, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
We don't passthrough IOMMU device to hwdom even if it is not used by
Xen.
Therefore exposing the properties that describe relationship between
master devices and IOMMUs does not make any sense.
According to the:
1. Documentation/devicetree/bindings/iommu/iommu.txt
2. Documentation/devicetree/bindings/pci/pci-iommu.txt
It is not entirely clear that documentation is from Linux.
Will clarify.
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
---
Changes V1 [1] -> V2:
- Only skip IOMMU specific properties of the master device if we
skip the corresponding IOMMU device
- Use "hwdom" over "Dom0"
[1]
https://lists.xenproject.org/archives/html/xen-devel/2019-10/msg00104.html
---
xen/arch/arm/domain_build.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 6d6dd52..a7321b8 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -480,10 +480,26 @@ static int __init write_properties(struct
domain *d, struct kernel_info *kinfo,
const struct dt_property *prop, *status = NULL;
int res = 0;
int had_dom0_bootargs = 0;
+ struct dt_device_node *iommu_node;
if ( kinfo->cmdline && kinfo->cmdline[0] )
bootargs = &kinfo->cmdline[0];
+ /*
+ * If we skip the IOMMU device when creating DT for hwdom (even if
+ * the IOMMU device is not used by Xen), we should also skip the
IOMMU
+ * specific properties of the master device behind it in order
to avoid
+ * exposing an half complete IOMMU bindings to hwdom.
+ * Use "iommu_node" as an indicator of the master device which
properties
+ * should be skipped.
+ */
+ iommu_node = dt_parse_phandle(node, "iommus", 0);
The code is slightly confusing to read. I don't think we should care
of invalid DT here, so let's only consider valid one.
Do you mean "the comment" is confusing to read?
For valid DT, any non-NULL return should point to an IOMMU. The
comment above suggests that all IOMMU will be skipped. However, the
check below (device_get_class(iommu_node)) will not return
DEVICE_IOMMU when there are not have a driver for the IOMMU.
So this needs to be clarified in the commit message.
Will do.
+ if ( iommu_node )
+ {
+ if ( device_get_class(iommu_node) != DEVICE_IOMMU )
+ iommu_node = NULL;
+ }
Could we gather the two conditions in one if?
Yes.
--
Regards,
Oleksandr Tyshchenko
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